The Fate of Small Valved Conduits Reconstructing the Right Ventricle Outflow Tract

C. E.. Diaz-Castrillon¹, M. Viegas², M. Castro-Medina³, N. Iyanna¹, L. Seese⁴, K. kobayashi⁵, S. Tarun¹, L. Da Fonseca Da Silva², V. Morell^2
1University of Pittsburgh, pittsburgh, Pennsylvania ²UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania ³UPMC Chilldren's Hospital of Pittsburgh, Pittsburgh, Pennsylvania ⁴University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania ⁵Univesity of pittsburgh medical center, Pittsburgh, Pennsylvania

Purpose: Small conduits used during Right Ventricular Outflow Tract (RVOT) surgery may become insufficient in size to accommodate the increasing blood flow demands. This study sought to characterize the failure pattern of small valved conduits and to evaluate other factors associated with early failure rather than growth rate.

Methods: We included patients between 2006-2021 that underwent a surgical repair of congenital heart anomaly involving an RVOT reconstruction procedure with either a Homograft or a PTFE valved conduit ≤ 12 mm. Perioperative and clinical outcomes were comparatively assessed between early reintervention group and non-early reintervention group, defined as the need for surgery or Cath-lab intervention during the first year of implantation. Primary outcomes were failure pattern and time to the first reintervention. Logistic regression was used to evaluate factors associated with early failure.

Results: In total, 68 patients with 73 conduits were included. The median age and weight were 10 days (IQR 7 – 123) and 3.4 kg (IQR 2.9 – 4.5), respectively. Truncus was the most common diagnosis in 58% (n= 42) of patients, followed by TOF (26%, n= 19). The median conduit diameter was 10 mm (9 - 11). 60.3% (n= 44) were PTFE and 39.7% (n= 29) homografts. Overall, 35.6% (n= 26) required an early intervention (15 PTFE and 11 Homograft) with a median time to the first intervention of 214 days (IQR 172 - 258) in contrast to 870 days ( IQR 581-1478) in the non-early group (n= 47).

The early failure group was nominally younger (18 vs. 9 days; p 0.18) and smaller (3.8 vs. 3.0; p 0.01). No significant differences were observed in diameter, conduit type, or pulmonary arteries cath interventions. In total, 50% (n= 12) had focal stenosis; 17% (n= 4) had diffuse narrowing, and 25% (n= 6) were replaced without conduit abnormalities (Figure). The increasing diameter was a protective factor for early failure (aOR 0.53, 95% CI 0.35 - 0.86) after controlling for age, conduit type, and pulmonary artery branch interventions.

Conclusion: Patients with small, valved conduits used in RVOT reconstructions often require reinterventions, with approximately one-third requiring such interventions within the first year after surgery. Conduit diameter was independently associated with decreased odds for early intervention after controlling for age and conduit type. It's worth noting that 25% of the early interventions occurred during other surgical procedures, even in the absence of any structural abnormalities in the conduit.

Identify the source of the funding for this research project: none